KANJI GUIDE
A wave. 波乱 is upheaval; 電波 is a radio wave.
A feather, and a wing. The character is two of them side by side.
The sky, and heaven with it. 天国 is paradise; 天気 is the weather.
Half of 瑠璃, the deep blue stone. On its own it is used mostly for its sound and its colour.